最近看到有个同事在遍历json数组的时候，用for循环写了一层有一层，那么是否有简便的写法呢？当然有了，下面就有用流的行驶，优雅的遍历数组，获取我们想要的数据

public static void main(String[] args) {String structure = "[{\"key\":\"111\",\"isRequired\":true,\"isNumber\":true,\"isFixed\":true},{\"key\":\"2\",\"isFixed\":true},{\"key\":\"3\",\"isNumber\":true},{\"key\":\"4\",\"isRequired\":true}]";JSONArray jsonArray;try {jsonArray = JSON.parseArray(structure);} catch (JSONException e) {System.err.println("Invalid JSON format: " + e.getMessage());return;}List<String> unitList = Optional.ofNullable(jsonArray).orElse(new JSONArray()).stream().filter(item -> item instanceof JSONObject).map(item -> {JSONObject jsonObject = (JSONObject) item;String key = jsonObject.getString("key");return key;}).collect(Collectors.toList());System.out.println(unitList);
}